Problem: Simplify the following expression: $k = \dfrac{20x + 16}{-20}$ You can assume $x \neq 0$.
Answer: Find the greatest common factor of the numerator and denominator. The numerator can be factored: $20x + 16 = (2\cdot2\cdot5 \cdot x) + (2\cdot2\cdot2\cdot2)$ The denominator can be factored: $-20 = - (2\cdot2\cdot5)$ The greatest common factor of all the terms is $4$ Factoring out $4$ gives us: $k = \dfrac{(4)(5x + 4)}{(4)(-5)}$ Dividing both the numerator and denominator by $4$ gives: $k = \dfrac{5x + 4}{-5}$